Debating with a Creationist.

Humans have 23 pairs of chromosomes while chimpanzees have 24. This, to said Creationist, is "proof" that evolution is untrue. I know about the 2nd human chromosome being longer, and analogous to 2 chimpanzee chromosomes. How do I explain the merge to him?

>>2
But that won't work, since it doesn't challenge his theory that a shift is impossible. And it doesn't help.
>>3
I'm not lying.